<?php
/**
 * CLogger class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CLogger records log messages in memory.
 *
 * CLogger implements the methods to retrieve the messages with
 * various filter conditions, including log levels and log categories.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CLogger.php 3206 2011-05-09 09:26:24Z qiang.xue $
 * @package system.logging
 * @since 1.0
 */
class CLogger extends CComponent
{
    const LEVEL_TRACE='trace';
    const LEVEL_WARNING='warning';
    const LEVEL_ERROR='error';
    const LEVEL_INFO='info';
    const LEVEL_PROFILE='profile';

    /**
     * @var integer how many messages should be logged before they are flushed to destinations.
     * Defaults to 10,000, meaning for every 10,000 messages, the {@link flush} method will be
     * automatically invoked once. If this is 0, it means messages will never be flushed automatically.
     * @since 1.1.0
     */
    public $autoFlush=10000;
    /**
     * @var boolean this property will be passed as the parameter to {@link flush()} when it is
     * called in {@link log()} due to the limit of {@link autoFlush} being reached.
     * By default, this property is false, meaning the filtered messages are still kept in the memory
     * by each log route after calling {@link flush()}. If this is true, the filtered messages
     * will be written to the actual medium each time {@link flush()} is called within {@link log()}.
     * @since 1.1.8
     */
    public $autoDump=false;
    /**
     * @var array log messages
     */
    private $_logs=array();
    /**
     * @var integer number of log messages
     */
    private $_logCount=0;
    /**
     * @var array log levels for filtering (used when filtering)
     */
    private $_levels;
    /**
     * @var array log categories for filtering (used when filtering)
     */
    private $_categories;
    /**
     * @var array the profiling results (category, token => time in seconds)
     * @since 1.0.6
     */
    private $_timings;

    /**
     * Logs a message.
     * Messages logged by this method may be retrieved back via {@link getLogs}.
     * @param string $message message to be logged
     * @param string $level level of the message (e.g. 'Trace', 'Warning', 'Error'). It is case-insensitive.
     * @param string $category category of the message (e.g. 'system.web'). It is case-insensitive.
     * @see getLogs
     */
    public function log($message,$level='info',$category='application')
    {
        $this->_logs[]=array($message,$level,$category,microtime(true));
        $this->_logCount++;
        if($this->autoFlush>0 && $this->_logCount>=$this->autoFlush)
        $this->flush($this->autoDump);
    }

    /**
     * Retrieves log messages.
     *
     * Messages may be filtered by log levels and/or categories.
     * A level filter is specified by a list of levels separated by comma or space
     * (e.g. 'trace, error'). A category filter is similar to level filter
     * (e.g. 'system, system.web'). A difference is that in category filter
     * you can use pattern like 'system.*' to indicate all categories starting
     * with 'system'.
     *
     * If you do not specify level filter, it will bring back logs at all levels.
     * The same applies to category filter.
     *
     * Level filter and category filter are combinational, i.e., only messages
     * satisfying both filter conditions will be returned.
     *
     * @param string $levels level filter
     * @param string $categories category filter
     * @return array list of messages. Each array elements represents one message
     * with the following structure:
     * array(
     *   [0] => message (string)
     *   [1] => level (string)
     *   [2] => category (string)
     *   [3] => timestamp (float, obtained by microtime(true));
     */
    public function getLogs($levels='',$categories='')
    {
        $this->_levels=preg_split('/[\s,]+/',strtolower($levels),-1,PREG_SPLIT_NO_EMPTY);
        $this->_categories=preg_split('/[\s,]+/',strtolower($categories),-1,PREG_SPLIT_NO_EMPTY);
        if(empty($levels) && empty($categories))
        return $this->_logs;
        else if(empty($levels))
        return array_values(array_filter(array_filter($this->_logs,array($this,'filterByCategory'))));
        else if(empty($categories))
        return array_values(array_filter(array_filter($this->_logs,array($this,'filterByLevel'))));
        else
        {
            $ret=array_values(array_filter(array_filter($this->_logs,array($this,'filterByLevel'))));
            return array_values(array_filter(array_filter($ret,array($this,'filterByCategory'))));
        }
    }

    /**
     * Filter function used by {@link getLogs}
     * @param array $value element to be filtered
     * @return array valid log, false if not.
     */
    private function filterByCategory($value)
    {
        foreach($this->_categories as $category)
        {
            $cat=strtolower($value[2]);
            if($cat===$category || (($c=rtrim($category,'.*'))!==$category && strpos($cat,$c)===0))
            return $value;
        }
        return false;
    }

    /**
     * Filter function used by {@link getLogs}
     * @param array $value element to be filtered
     * @return array valid log, false if not.
     */
    private function filterByLevel($value)
    {
        return in_array(strtolower($value[1]),$this->_levels)?$value:false;
    }

    /**
     * Returns the total time for serving the current request.
     * This method calculates the difference between now and the timestamp
     * defined by constant YII_BEGIN_TIME.
     * To estimate the execution time more accurately, the constant should
     * be defined as early as possible (best at the beginning of the entry script.)
     * @return float the total time for serving the current request.
     */
    public function getExecutionTime()
    {
        return microtime(true)-YII_BEGIN_TIME;
    }

    /**
     * Returns the memory usage of the current application.
     * This method relies on the PHP function memory_get_usage().
     * If it is not available, the method will attempt to use OS programs
     * to determine the memory usage. A value 0 will be returned if the
     * memory usage can still not be determined.
     * @return integer memory usage of the application (in bytes).
     */
    public function getMemoryUsage()
    {
        if(function_exists('memory_get_usage'))
        return memory_get_usage();
        else
        {
            $output=array();
            if(strncmp(PHP_OS,'WIN',3)===0)
            {
                exec('tasklist /FI "PID eq ' . getmypid() . '" /FO LIST',$output);
                return isset($output[5])?preg_replace('/[\D]/','',$output[5])*1024 : 0;
            }
            else
            {
                $pid=getmypid();
                exec("ps -eo%mem,rss,pid | grep $pid", $output);
                $output=explode("  ",$output[0]);
                return isset($output[1]) ? $output[1]*1024 : 0;
            }
        }
    }

    /**
     * Returns the profiling results.
     * The results may be filtered by token and/or category.
     * If no filter is specified, the returned results would be an array with each element
     * being array($token,$category,$time).
     * If a filter is specified, the results would be an array of timings.
     * @param string $token token filter. Defaults to null, meaning not filtered by token.
     * @param string $category category filter. Defaults to null, meaning not filtered by category.
     * @param boolean $refresh whether to refresh the internal timing calculations. If false,
     * only the first time calling this method will the timings be calculated internally.
     * @return array the profiling results.
     * @since 1.0.6
     */
    public function getProfilingResults($token=null,$category=null,$refresh=false)
    {
        if($this->_timings===null || $refresh)
        $this->calculateTimings();
        if($token===null && $category===null)
        return $this->_timings;
        $results=array();
        foreach($this->_timings as $timing)
        {
            if(($category===null || $timing[1]===$category) && ($token===null || $timing[0]===$token))
            $results[]=$timing[2];
        }
        return $results;
    }

    private function calculateTimings()
    {
        $this->_timings=array();

        $stack=array();
        foreach($this->_logs as $log)
        {
            if($log[1]!==CLogger::LEVEL_PROFILE)
            continue;
            list($message,$level,$category,$timestamp)=$log;
            if(!strncasecmp($message,'begin:',6))
            {
                $log[0]=substr($message,6);
                $stack[]=$log;
            }
            else if(!strncasecmp($message,'end:',4))
            {
                $token=substr($message,4);
                if(($last=array_pop($stack))!==null && $last[0]===$token)
                {
                    $delta=$log[3]-$last[3];
                    $this->_timings[]=array($message,$category,$delta);
                }
                else
                throw new CException(Yii::t('yii','CProfileLogRoute found a mismatching code block "{token}". Make sure the calls to Yii::beginProfile() and Yii::endProfile() be properly nested.',
                array('{token}'=>$token)));
            }
        }

        $now=microtime(true);
        while(($last=array_pop($stack))!==null)
        {
            $delta=$now-$last[3];
            $this->_timings[]=array($last[0],$last[2],$delta);
        }
    }

    /**
     * Removes all recorded messages from the memory.
     * This method will raise an {@link onFlush} event.
     * The attached event handlers can process the log messages before they are removed.
     * @param boolean $dumpLogs whether to process the logs
     * @since 1.1.0
     */
    public function flush($dumpLogs=false)
    {
        $this->onFlush(new CEvent($this, array('dumpLogs'=>$dumpLogs)));
        $this->_logs=array();
        $this->_logCount=0;
    }

    /**
     * Raises an <code>onFlush</code> event.
     * @param CEvent $event the event parameter
     * @since 1.1.0
     */
    public function onFlush($event)
    {
        $this->raiseEvent('onFlush', $event);
    }
}
